Is an opiate antagonist that may in recovery from alcohol dependence.

The term antagonist denotes a compound that occupies a receptor, but does not activate the neuron. Naltrexone is an opiate antagonist that may help in recovery from alcohol dependence. The goal of consuming naltrexone is
 to reduce and suppress cravings for alcohol or opiate drugs and to prevent
 opioids from working in the body.

By water evaporation from the leaves is created a negative pressure at the top of the tree that promotes the ascension  of the water through channels that are called xylem. there are also two molecule forces that are involved: the intra-water molecules cohesion (water molecules stick to each other) and the adhesion when the water molecules stick to the channels they are running in. this is what enables water to go from the roots to the top of a tall tree.